Posts about Life Science

Europe Bans Certain Pesticides, USA Just Keeps Looking, Bees Keep Dying

For years the bee colony collapse disorder has been showing the difficulty of the scientific inquiry process. And that difficulty often becomes more difficult if interests with lots of money at stake want to block certain conclusions.

One-Third of U.S. Honeybee Colonies Died Last Winter, Threatening Food Supply

Multiple factors — pesticides, fungicides, parasites, viruses and malnutrition — are believed to cause the losses, which were officially announced today by a consortium of academic researchers, beekeepers and Department of Agriculture scientists.

“We’re getting closer and closer to the point where we don’t have enough bees in this country to meet pollination demands,” said entomologist Dennis vanEngelstorp of the University of Maryland, who led the survey documenting the declines.

Beekeepers lost 31 percent of their colonies in late 2012 and early 2013, roughly double what’s considered acceptable attrition through natural causes. The losses are in keeping with rates documented since 2006, when beekeeper concerns prompted the first nationwide survey of honeybee health. Hopes raised by drop in rates of loss to 22 percent in 2011-2012 were wiped out by the new numbers.

Most losses reported in the latest survey, however, don’t actually fit the CCD profile. And though CCD is largely undocumented in western Europe, honeybee losses there have also been dramatic. In fact, CCD seems to be declining, even as total losses mount. The honeybees are simply dying.

“Even if CCD went away, we’d still have tremendous losses,” said entomologist Diana Cox-Foster at Pennsylvania State University. “CCD losses are like the straw that breaks the camel’s back. The system has many other issues.”

Continue reading

Cell Aging and Limits Due to Telomeres

When cells divide the process fails to copy DNA all the way to the end. Telomeres are are the end of DNA strands, as essentially a buffer of material that won’t cause information to be lost when part of the telomere isn’t copied. As DNA is copied, as new cells are created, the length of telomeres at the end is reduced. Once the telomeres are gone the cell will no longer divide.

The 2009 Nobel Prize in Physiology or Medicine went to 3 scientists for discovering how the chromosomes can be copied in a complete way during cell divisions and how they are protected against degradation. The Nobel Laureates have shown that the solution is to be found in the ends of the chromosomes – the telomeres – and in an enzyme that forms them – telomerase.

There is some debate over the benefit of the mechanism of cells not dividing do to lack of telomere. This can prevent cancerous cells from replicating (once they replicate to the extent that the necessary telomere buffer is gone). It is also seen that as telomeres get shorter the cells become more likely to become cancerous.

Cancer also can stimulate the production of telomerase which can stop telomeres from getting shorter as cells divide and thus allow the cancer cells to keep dividing (thus producing more cancer cell and increasing the amount of cancerous cells). Using telomerase to allow health cells to avoid the limits of division is being researched.

Are Telomeres the Key to Aging and Cancer? (University of Utah)

An enzyme named telomerase adds bases to the ends of telomeres. In young cells, telomerase keeps telomeres from wearing down too much. But as cells divide repeatedly, there is not enough telomerase, so the telomeres grow shorter and the cells age.

Cells normally can divide only about 50 to 70 times, with telomeres getting progressively shorter until the cells become senescent, die or sustain genetic damage that can cause cancer.

shorter telomeres are associated with shorter lives. Among people older than 60, those with shorter telomeres were three times more likely to die from heart disease and eight times more likely to die from infectious disease.

While telomere shortening has been linked to the aging process, it is not yet known whether shorter telomeres are just a sign of aging – like gray hair – or actually contribute to aging.

Related: The Naked Mole Rat is the Only Known Cancerless AnimalWebcast of a T-cell Killing a Cancerous CellRNA interference webcast

Huge Human Population Boom 40,000 to 50,000 Years Ago

Interesting open access paper on looking at the Y-chromosome to explore our ancestry: A calibrated human Y-chromosomal phylogeny based on resequencing. I can’t understand all the details but the basic idea isn’t that complicated. It is interesting to see these details as are the conclusions that can be drawn: that we had a big explosion of human population o 41,000–52,000 years ago.

This population explosion occurred, between the first expansion of modern humans out of Africa 60,000 to 70,000 years ago and the Neolithic expansions of people in several parts of the world starting 10,000 years ago.

“We think this second, previously unknown population boom, may have occurred as humans adapted to their new environment after the first out-of-Africa expansion,” says Dr Qasim Ayub, lead author from the Wellcome Trust Sanger institute. “We think that when humans moved from the horn of Africa to Asia, Australia and eventually Europe, they remained in small groups by the coasts. It took them tens of thousands of years to adapt to the mountainous, forested surroundings on the inner continents. However, once their genetic makeup was suited to these new environments, the population increased extremely rapidly as the groups travelled inland and took advantage of the abundance of space and food.”

The work highlights how it is now possible to obtain new biological insights from existing DNA sequencing data sets, and the value of sharing data. The majority of the DNA information used for this study was obtained from freely-available online data-sets.

This is the first time researchers have used the information from large-scale DNA sequencing to create an accurate family tree of the Y chromosome, from which the inferences about human population history could be made.

Full press release

Related: Laser Tool Creates “blueprints” of Archeology SitesHHMI on Science 2.0: Information RevolutionScientists crack 40-year-old DNA puzzle

CDC Again Stresses Urgent Need to Adjust Practices or Pay a Steep Price

Untreatable and hard-to-treat infections from Carbapenem-resistant Enterobacteriaceae (CRE) germs are on the rise among patients in medical facilities. CRE germs have become resistant to all or nearly all the antibiotics we have today. Types of CRE include Klebsiella pneumoniae Carbapenemase (KPC) and New Delhi metallo-beta-lactamase (NDM). By following the United States Center for Disease Control (CDC) guidelines, we can slow the penetration of CRE infections in hospitals and other medical facilities and potentially spread to otherwise healthy people outside of medical facilities.

The CDC has worked with hospitals to successfully apply these measures. The CDC worked with Florida to stop a year-long CRE outbreak in a long-term acute care hospital. With the improved use of CDC recommendations (such as educating staff; dedicating staff, rooms, and equipment to patients with CRE; and improving use of gloves and gowns) the percentage of patients who got CRE at the facility dropped from 44% to 0.

One travesty has been how poorly health care professionals have been about prescribe antibiotics wisely We need to improve and follow CDC antibiotics guidelines (stop the overuse of antibiotics) and use culture results (for patients undergoing treatment) to modify prescriptions, if needed. Antibiotic overuse contributes to the growing problems of Clostridium difficile (c-diff) infection and antibiotic resistance in healthcare facilities. Studies indicate that nearly 50% of antimicrobial use in hospitals is unnecessary or inappropriate (per CDC web site).

Israel decreased CRE infection rates in all 27 of its hospitals by more than 70% in one year with a coordinated prevention program. The USA is at a critical time in which CRE infections could be controlled if addressed in a rapid, coordinated, and consistent effort by doctors, nurses, lab staff, medical facility leadership, health departments/states, policy makers, and the federal government.

As I have been saying for years the damage we are creating due to our actions around the use and abuse of antibiotics is likely to kill tens of thousands, or more people. Because the deaths are delayed and often not dramatic we have continued dangerous practices for years when we know better. It is a shame we are condemning so many to increased risks. The CDC, and others, are doing good work, unfortunately too much bad work is continuing in the face of evidence of how dangerous that is.

Related: CDC Urges Increased Effort to Reduce Drug-Resistant Infections (2006)Key scientific articles on Healthcare Associated Infections via CDCOur Dangerous Antibiotic Practices Carry Great RisksDangerous Drug-Resistant Strains of TB are a Growing Threat

People are Superorganisms With Microbiomes of Thousands of Species

In a recent article in National Geographic Carl Zimmer has again done a good job of explaining the complex interaction between our bodies and the bacteria and microbes that make us sick, and keep us healthy.

The damage done by our indiscriminate use of antibiotics is not just the long term resistance that we create in bacteria (making the future more dangerous for people) that I have written about numerous times but it also endangers the person taking the anti-biotics in the short term. Sometimes the other damage is a tradeoff that should be accepted. But far too often we ignore the damage taking antibiotics too often does.

When You Swallow A Grenade

While antibiotics can discriminate between us and them, however, they can’t discriminate between them and them–between the bacteria that are making us sick and then ones we carry when we’re healthy. When we take a pill of vancomycin, it’s like swallowing a grenade. It may kill our enemy, but it kills a lot of bystanders, too.

If you think of the human genome as all the genes it takes to run a human body, the 20,000 protein-coding genes found in our own DNA are not enough. We are a superorganism that deploys as many as 20 million genes.

Before he started taking antibiotics, the scientists identified 41 species in a stool sample. By day 11, they only found 13. Six weeks after the antibiotics, the man was back up to 38 species. But the species he carried six weeks after the antibiotics did not represent that same kind of diversity he had before he took them. A number of major groups of bacteria were still missing.

They found that children who took antibiotics were at greater risk of developing inflammatory bowel disease later in life. The more antibiotics they took, the greater the risk. Similar studies have found a potential link to asthma as well.

The human body contains trillions of microorganisms — outnumbering human cells by 10 to 1. Because of their small size, however, microorganisms make up only about 1% to 3% of the body’s mass, but play a vital role in human health.

Where doctors had previously isolated only a few hundred bacterial species from the body, Human Microbiome Project (HMP) researchers now calculate that more than 10,000 microbial species occupy the human ecosystem. Moreover, researchers calculate that they have identified between 81% and 99% of all microorganismal genera in healthy adults.

“Humans don’t have all the enzymes we need to digest our own diet,” said Lita Proctor, Ph.D., NHGRI’s HMP program manager. “Microbes in the gut break down many of the proteins, lipids and carbohydrates in our diet into nutrients that we can then absorb. Moreover, the microbes produce beneficial compounds, like vitamins and anti-inflammatories that our genome cannot produce.” Anti-inflammatories are compounds that regulate some of the immune system’s response to disease, such as swelling.

“Enabling disease-specific studies is the whole point of the Human Microbiome Project,” said Barbara Methé, Ph.D., of the J. Craig Venter Institute, Rockville, MD, and lead co-author of the Nature paper on the framework for current and future human microbiome research. “Now that we understand what the normal human microbiome looks like, we should be able to understand how changes in the microbiome are associated with, or even cause, illnesses.”

Read the full NIH press release on the normal bacterial makeup of the body

Related: Tracking the Ecosystem Within UsWhat Happens If the Overuse of Antibiotics Leads to Them No Longer Working?Antibacterial Products May Do More Harm Than GoodAntibiotics Too Often Prescribed for Sinus Woes

Human Gene Origins: 37% Bacterial, 35% Animal, 28% Eukaryotic

The percent of human genes that emerged in various stages of evolution: 37% bacterial, 28% eukaryotic, 16% animal, 13% vertebrate, 6% primate. The history that brought us to where we are is amazing. Eukaryotes include animals, plants, amoebae, flagellates, amoeboflagellates, fungi and plastids (including algae). So eukaryotic genes are those common to us and other non-animal eukaryotes while those classified as animal genes are shared by animals but not non-animal eukaryotes.

We are living in a bacterial world, and it’s impacting us more than previously thought by Lisa Zyga

Bacterial signaling is not only essential for development, it also helps animals maintain homeostasis, keeping us healthy and happy. As research has shown, bacteria in the gut can communicate with the brain through the central nervous system. Studies have found that mice without certain bacteria have defects in brain regions that control anxiety and depression-like behavior. Bacterial signaling also plays an essential role in guarding an animal’s immune system. Disturbing these bacterial signaling pathways can lead to diseases such as diabetes, inflammatory bowel disease, and infections. Studies also suggest that many of the pathogens that cause disease in animals have “hijacked” these bacterial communication channels that originally evolved to maintain a balance between the animal and hundreds of beneficial bacterial species.

Scientists have also discovered that bacteria in the human gut adapts to changing diets. For example, most Americans have a gut microbiome that is optimized for digesting a high-fat, high-protein diet, while people in rural Amazonas, Venezuela, have gut microbes better suited for breaking down complex carbohydrates. Some people in Japan even have a gut bacterium that can digest seaweed. Researchers think the gut microbiome adapts in two ways: by adding or removing certain bacteria species, and by transferring the desired genes from one bacterium to another through horizontal gene transfer. Both host and bacteria benefit from this kind of symbiotic relationship, which researchers think is much more widespread than previously thought.

We want badly for the message in ‘Animals in a bacterial world,’ to be a call for the necessary disappearance of the old boundaries between life science departments (e.g., Depts of Zoology, Botany, Microbiology, etc.) in universities, and societies (e.g., the American Society for Microbiology, etc.). We also want the message disseminated in college and university classes from introductory biology to advanced courses in the various topic areas of our paper.”

Very cool stuff. This amazing facts scientists discover provide an amazing view of the world we live in and how interconnected we are to other life forms in ways we don’t normally think of.

Related: People’s Bodies Carry More Bacterial Cells than Human CellsMicrobes Flourish In Healthy PeopleTracking the Ecosystem Within UsForeign Cells Outnumber Human Cells in Our BodiesBacteria Beneficial to Human Health

Homing Pigeons May Use Low Frequency Sound Maps To Locate Home

Mystery of Lost Homing Pigeons Finally Solved

Prior research had shown that birds hear incredibly low-frequency sound waves of about 0.1 Hertz, or a tenth of a cycle per second. These infrasound waves may emanate from in the ocean and create tiny disturbances in the atmosphere. Hagstrum began to think the birds used infrasound for navigation.

on the odd day when the birds reached home from Jersey Hill without problems, the infrasound traveled between the two locations. At the other locations where pigeons headed off in the wrong direction, he showed that wind currents channeled the infrasound waves in that direction.

The explanation may solve other mysteries about pigeons — for instance, why they circle around before heading off in one direction. Because the sound waves are so long, but the birds’ ear canals are tiny, they need to circle to reconstruct the wave and figure out which way they are oriented, he said.

More interesting scientific inquiry. It is very interesting to learn what scientists are learning about our world – even when the conclusions are still preliminary and may be adjusted or refuted.

Related: Pigeon Solves Box and Banana ProblemCool Research on CrowsBird Using Bait to FishMoth Jams Bat Sonar

How Caffeine Affects Your Body

From the video by Alex Dainis: Caffeine prevents adenosine from slowing down your nervous system, by binding to the same receptors adenosine would. Caffeine also stimulates the production of adrenaline. And it increases the amount of dopamine present. The average half life of caffeine in the human body is about 6 hours.

Related: Does Diet Soda Result in Weight Gain?Mental Pick-Me-Ups: The Coming BoomRitalin Doesn’t Show Long Term Effectiveness for ADHD

I have been curious about the caffeine content of various drinks and writing this post is a good enough reason to actually look it up.

  • expresso (2oz) 100 mg (varies – 60 mg to 180 mg)
  • coffee (8oz) 100 mg – this can vary quite a bit, 50 to over 100 mg is common. Brewed coffee has more caffeine 100-200 mg.
  • Red Bull (8.2 oz) 80 mg
  • tea (8oz) 20 to 80 mg (depending on strength and type, can also be higher, green tea is on the lower end)
  • Mountain Dew (12 oz) 54 mg (diet has 54 mg also)
  • Diet Coke 46 mg (regular Coke 34mg)
  • Pepsi 38 mg, Diet Pepsi 36 mg

Sprite, 7Up and some root beers have no caffeine.
Chocolate can also be a significant source of caffeine – dark chocolate can have over 80 mg per 100 g (approximately 4 ounces).

Cancer Cells in Blind Mole Rats ‘commit suicide’

Cancer cells in blind mole rats ‘commit suicide’

Blind mole rats don’t get cancer, and geneticists have worked out why — their cells kill themselves with a poisonous protein when they multiply too much.

Blind mole rats, which live in underground burrows throughout Southern and Eastern Africa, and the Middle East, are fascinating creatures. The naked mole rat, in particular, is the only cold-blooded mammal known to man, doesn’t experience pain, and is also arguably the only mammal (along with the Damaraland mole rat) to demonstrate eusociality — that is, they live in large hierarchical communities with a queen and workers, like ants or bees.

They’re also cancer-proof, which was found in 2011 to be down to a gene that stops cancerous cells from forming. The same team thought that two other cancer-proof mole rat species might have similar genes, but instead it turns out that they do develop cancerous cells — it’s just that those cells are programmed to destroy themselves if they become dangerous.

Very interesting research. The results of evolution are amazing. And while turning the medical research discoveries into workable treatments for people is very difficult the continued increase in our knowledge helps us find treatments that work.

Related: Webcast of a T-cell Killing a Cancerous CellSynthetic Biologists Design a Gene that Forces Cancer Cells to Commit Suicide

Evolution Follows a Predictable Genetic Pattern

Far from random, evolution follows a predictable genetic pattern

The researchers carried out a survey of DNA sequences from 29 distantly related insect species, the largest sample of organisms yet examined for a single evolutionary trait. Fourteen of these species have evolved a nearly identical characteristic due to one external influence — they feed on plants that produce cardenolides, a class of steroid-like cardiotoxins that are a natural defense for plants such as milkweed and dogbane.

Though separated by 300 million years of evolution, these diverse insects — which include beetles, butterflies and aphids — experienced changes to a key protein called sodium-potassium adenosine triphosphatase, or the sodium-potassium pump, which regulates a cell’s crucial sodium-to-potassium ratio. The protein in these insects eventually evolved a resistance to cardenolides, which usually cripple the protein’s ability to “pump” potassium into cells and excess sodium out.

Andolfatto and his co-authors examined the sodium-potassium pump protein because of its well-known sensitivity to cardenolides. In order to function properly in a wide variety of physiological contexts, cells must be able to control levels of potassium and sodium. Situated on the cell membrane, the protein generates a desired potassium to sodium ratio by “pumping” three sodium atoms out of the cell for every two potassium atoms it brings in.

Cardenolides disrupt the exchange of potassium and sodium, essentially shutting down the protein, Andolfatto said. The human genome contains four copies of the pump protein, and it is a candidate gene for a number of human genetic disorders, including salt-sensitive hypertension and migraines. In addition, humans have long used low doses of cardenolides medicinally for purposes such as controlling heart arrhythmia and congestive heart failure.

Cool stuff. It makes sense to me which is nice (it is nice to get confirmation that I find what actually exists is sensible). When things that are true just seem crazy it is a bit disconcerting – like quantum mechanics. It is fun to read stuff that totally shakes up preconceived notions, but even then it is nice once I think understand it to find it sensible.

Related: All present-day Life on Earth Has A Single AncestorCambrian Explosion SongBacteriophages: The Most Common Life-Like Form on EarthMicrocosm by Carl Zimmer

Does Diet Soda Result in Weight Gain?

Most of us want medical studies to provide clearer (more certain, more specific, more universal) indications than they actually provide. The conclusion of medical studies are often very clouded. Each person has a myriad of complex factors effecting how nutrition, activity and medication will affect us. Certain general conclusion can be drawn but it is very complex and difficult to universally state without various equivocations.

Advice For Diet Soda Lovers: Skip The Chips

Researchers at the University of North Carolina-Chapel Hill found that diet soda drinkers who ate a so-called “prudent” diet, rich in fruit, fish, vegetables, whole grains, nuts and milk, were significantly less likely to develop metabolic syndrome over 20 years than those who ate a “Western diet” heavy in fried foods, meats and sugars.

Metabolic syndrome is a condition characterized by excess abdominal fat, elevated blood sugar, high blood pressure, elevated triglycerides and low HDL cholesterol. About 32 percent of the participants in the “Western diet” cluster developed the condition.

The question of whether diet soda truly helps people manage their weight turns out to be a very tough one to answer.

Conflicting findings abound. A large study published in the New England Journal of Medcine last year found that diet soda had no effect on weight. But another one, published in 2008, found that drinking more than three diet drinks a day led to weight gain.

I would like to know, with much greater certainty what nutritional and food related advice I need to consider when making my choices. To a significant degree I think there is going to be quite a bit of uncertainty (much more than we want) for at least the next 30 years (projecting far out into the future with any accuracy seems very difficult to me.

I am skeptical of purely correlational results. You can try to have similar subsets of people but that is actually hard and if you allow for similar groups and then let the choose something (like diet sodas or not) the chance of that actually being a significant choice that results in many other decisions being different between the subgroups seems a big risk (that makes accepting the correlation as evidence as risky). When you have a scientific explanation it makes the evidence much more compelling, but it is also easy to be taken in by explanations meant to fit the results of a study.

I can believe diet soda can do some bad things to your health. I believe if you are trying to reduce your weight by reducing calories drinking diet soda in place of sugary soda is a big help. I can believe drinking water instead of diet soda would be even better. I want caffeine and don’t like coffee. I have cut down drinking Mountain Dew to less than 2 a week. I have substituted diet soda over the last year. I am not sure that is the right choice, but it is the one I have made so far.

Related: Science Continues to Explore Causes of Weight GainStudy Shows Weight Loss From Calorie Reduction Not Low Fat or Low CarbAnother Paper Questions Scientific Paper AccuracyContradictory Medical Studies

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